The Minimum Clinically Important Difference of the International Consultation on Incontinence Questionnaires (ICIQ-UI SF and ICIQ-LUTSqol)

Abstract

Objective: To estimate the minimum clinically important difference (MCID) of the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) and the International Consultation on Incontinence Questionnaire-Lower Urinary Tract Symptoms Quality of Life (ICIQ-LUTSqol) using both anchor-based and distribution-based methods for women with stress urinary incontinence undergoing nonsurgical treatment.

Materials and methods: Data from a randomized clinical trial evaluating efficacy of a nonsurgical intervention in women with stress urinary incontinence were used for analyses. The overall score of ICIQ-UI SF ranges from 0 to 21, with greater values indicating increased severity. The ICIQ-LUTSqol ranges from 19 to 76, with greater values indicating increased impact on quality of life. Instruments used in the anchor-based method were the Patient Global Impression of Improvement, patient satisfaction, 1-hour pad test and the incontinence episode frequency. The distribution-based method used an effect size of 0.5 standard deviation. Triangulation of findings was used to converge on a single value of MCID.

Results: At 12-month post-treatment, 106 (88.3%) participants completed the follow-up and were included in the analysis. Anchor-based MCIDs of the ICIQ-UI SF were between 3.4 and 4.4, while the distribution-based MCID was 1.7. Anchor-based MCIDs of the ICIQ-LUTSqol were between 4.8 and 6.9, while the distribution-based MCID was 5.2. Triangulation of findings showed that MCIDs of 4 for ICIQ-UI SF and 6 for ICIQ-LUTSqol were the most appropriate.

Conclusion: For women undergoing nonsurgical treatments for incontinence, reductions of 4 and 6 points in ICIQ-UI SF and ICIQ-LUTSqol, respectively are perceived as clinically meaningful.